Just a question. Are you trying to sync using Activesync? In Vista, you still have to download and install Activesync's renamed equivalent Windows Mobile Device Center (WMDC). You must have these if you flashed your ROM. Let us know what is happening. I've had no problems with AS4.5 or WMDC by USB or Bluetooth. Also, there is a whole forum devoted to it here if you want to see:
http://forums.microsoft.com/WindowsM...1762&SiteID=65
Advice is usually delete mobile adapter and USB connection in device manager/redetect, remove/remake partnerships with reboot of both device and PC, uninstall/ reinstall AS/WMDC, hard reset device, etc....